[R] standard error very high in maximum liklihood fitting

Ben Bolker bbolker at gmail.com
Tue Feb 12 17:13:27 CET 2013


Abu Naser <likhonnaser <at> hotmail.com> writes:

> I have been trying to fit my data (only right censored)
>  with gumbel distribution using fitdistrplus. I am
> getting very high standard error. I have been wondering why.
> The followings are the outputs:
> 
> fit1=fitdistcens(dr0, "gumbel", start=list(a=99, b=0.6), 
> optim.method= "L-BFGS-B", lower = 0.0,
> upper = Inf)
> > summary(fit1)

  [snip]

>     estimate Std. Error
> a 97.8260371    3115.09
> b  0.1115094     173.79
> Loglikelihood:  -9.749883e-10   AIC:  4   BIC:  21.21178 

 [snip]

 Impossible to say without a reproducible example.  It seems 
very suspicious that your log-likelihood is almost exactly zero.
Do you have a very small data set?



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